Solar Battery Storage — UK 2026 Guide
Everything you need to know about home batteries — sizing, cost, brands, backup power and tariff stacking — from working MCS-registered installers in Devon.
Why add a battery?
Without a battery, you typically use only 25–35% of the electricity your panels make. Add storage and that jumps to 70–85%, doubling your savings. Batteries also let you charge cheaply on Octopus Go or Cosy and discharge during the expensive 4–7pm peak.
2026 UK battery prices
| Battery size | Best for | Installed price (plus VAT) |
|---|---|---|
| 5 kWh | 1–2 bed, low usage | £4,000 – £5,500 |
| 10 kWh | 3-bed family home | £5,500 – £7,000 |
| 13.5 kWh (Powerwall) | 4-bed + EV | £8,500 – £10,500 |
| 15–20 kWh stacked | Heat pump + EV | £8,500 – £12,000 |
| + EPS / backup wiring | Power-cut resilience | + £400 – £800 |
All prices include hybrid/AC-coupled inverter where required, isolators, monitoring, MCS sign-off and DNO G99 notification. Domestic VAT is currently 0%.
Brands we install
- GivEnergy — UK-made, brilliant app, 12-year warranty
- Tesla Powerwall — premium, slick backup, 13.5 kWh
- Sunsynk — flexible hybrid inverter, modular batteries
- Fox ESS — strong value, modular up to 20+ kWh
- SolaX — good for retrofit, AC-coupled options
We have no installer kickbacks tied to a single brand — we recommend what fits your property and tariff.
Stacking with cheap-rate tariffs
Even if you have no solar yet, a battery alone can save £400–£700/year by charging on a cheap overnight rate (e.g. 7p/kWh) and discharging during the day at the standard rate (~28p/kWh). Combine with solar and Smart Export Guarantee for the best return.
Free battery survey across Devon
We'll size it properly, model your savings honestly and quote fixed-price.
Frequently Asked Questions
How much does a solar battery cost in 2026?
A 5kWh home battery costs £4,000–£5,500 plus VAT installed. A 10kWh battery is £5,500–£7,000 plus VAT. Domestic batteries are currently zero-rated for VAT in the UK until March 2027.
What size battery do I need with my solar panels?
A rough rule: match battery kWh to about half your daily electricity use. A 3-bed home using 9 kWh/day pairs well with a 5kWh battery; a 4-bed with EV usually needs 10–13 kWh.
Can I add a battery to existing solar panels?
Yes — almost any existing solar PV system can have AC-coupled battery storage retrofitted. We commonly fit GivEnergy, Tesla Powerwall, Sunsynk and Fox ESS batteries to systems we did not originally install.
Will a solar battery power my house in a power cut?
Only if it has Emergency Power Supply (EPS) or whole-house backup wired in at install. Tesla Powerwall, GivEnergy AIO and Sunsynk all support this — we configure it as part of the install.
How long do solar batteries last?
Modern lithium-iron-phosphate (LFP) batteries are warrantied for 10–12 years and typically last 15+ years at 80% capacity. We only fit LFP chemistry — not the older NMC.